Russian scientists' import-substituting innovation hits the cover of an American journal
Lobachevsky University scientists from the Research Institute for Chemistry, together with their colleagues from the Mendeleev Russian University of Chemical Technology, have designed a process for the automatic synthesis of metal nanoparticles.
Chemists have already succeeded in producing nanoparticles of aluminium, magnesium, nickel and titanium smaller than 50 nm, which are unique in their purity. These nanoparticles are used to prepare antibacterial and high-strength conductive composite coatings. The nanopowders can also be used as feedstock for metal 3D printing technology.
The newly developed technology allows scientists at UNN and Mendeleev Russian University of Chemical Technology to conduct direct synthesis of high-purity substances for the needs of import substitution and development of domestic microelectronics. The core of the technology is the use of the induction-flow levitation (IFL) method. Metal is melted using a high-frequency electromagnetic field created by a countercurrent inductor.
The induction currents pass through the metal, bringing it into a state of levitation and preventing it from coming into contact with the apparatus. A drop of molten metal is blown by a stream of inert gas (helium, or argon). The metal evaporates and the atomic vapour condenses on the gas molecules to form nanoparticles. The higher the velocity of the gas flow, the smaller and more homogeneous the size of nanoparticles.
UNN researchers succeeded in achieving stable levitation and high synthesis yield. By changing the synthesis parameters, scientists have been able to control the size of nanoparticles and hence their characteristics.
"We have developed a fully automated direct high-throughput nanoparticle synthesis apparatus from scratch. The method is quite complex in terms of instrumentation, but the automation has made it possible to run it at the touch of a button. We use high-precision pressure and gas flow sensors, 'in-situ' gas analysers, which have feedback to other modules in the installation. By investigating the temperature-levitation properties, we have tested different types of countercurrent inductors and found the optimum one. The unit can be scaled up, increasing the volume of the end product," explains Andrey Vorotyntsev, one of the authors of the project, Head of the Laboratory of Engineering Chemistry at the UNN Research Institute for Chemistry.
The research was conducted within the framework of the grant of the Russian Science Foundation "Physico-chemical principles of controlled synthesis of nanoparticles, nanoclusters, and volatile hydrides by levitation in induction flow" and with the financial support of the Priority 2030 program of Lobachevsky University. The work is being carried out under a joint project of the Tula-TECH Research and Education Centre, Mendeleev University of Chemical Technology, and Lobachevsky University scientists.
"Our results have been published in the American journal ACS Sustainable Chemistry & Engineering and even have appeared on the cover of this journal. We believe that in the conditions of sanctions and limited access to scientometric systems, this is an international success, our first cover," said Andrey Vorotyntsev.
The induction-flow levitation technique was first developed in the 1960s by M.Ya. Gen and A.V. Miller, scientists from the Semenov Institute of Chemical Physics of the Russian Academy of Sciences. The method made it possible to carry out many pioneering studies on the properties of submicron powders of metals, alloys and metal oxides and to apply them in various fields of science and technology. Today, it is one of the most promising methods for producing nanoparticles. It is superior to other methods in terms of environmental friendliness, cost-effectiveness and production speed, and also makes it possible to control the characteristics of nanoparticles more precisely. Thanks to the research of Nizhny Novgorod scientists, the method can be more widely introduced into the Russian industry.